Ground working tooth



March 27, 1962 P. v. LARSEN ET AL 3,026,947

GROUND WORKING TOOTH Filed Nov. 27, 1959 2 Sheets-Sheet 1 March 27, 1962P. v. LARSEN ET AL 3,026,947

GROUND WORKING TOOTH Filed Nov. 27, 1959 21 f5] ppczagQzbis'er-z O O s0?? sol/ 6; w. @165 United States Patent 3,026,947 GRGUND WORKING TOOTHPaul V. Larsen and Paul Eyolfson, Portland, George W. Hill, Newberg, andEugene W. Dils, Jr., Portland, Greg; said Larsen, said Eyolfson, andsaid Hill assignors to Esco Corporation, a corporation of Oregon FiledNov. 27, 1959, Ser. No. 855,713 15 Claims. (Cl. 172762) This inventionrelates to a ground working tooth and, more particularly, to teethincluding replacement adapters and points adapted for use onpower-driven rippers, excavating and loading buckets, dippers, scoops,scarifiers, and similar ground working tools.

This application is related to the copending, co-owned application ofPaul V. Larsen, Serial No. 729,858, filed April 21, 1958, now Patent No.2,919,506, and reference may be had to that application for additionaldetails of construction.

In a ground working device of the aforementioned character, a shank orbase is provided which in turn provides a supporting nose on which ismounted a tooth point or an adapter for supporting a tooth point. Thepresent invention is concerned primarily with the nose, the hollow pointor socket element removably carried by the nose, and with means foruniting these elements. The nose may be the adapter nose, or it may bethe nose formed integrally with a base member such as the ripper shankor lip of a bucket, etc., and the socket element may be the cap or pointportion of a tooth received upon the nose of the adapter itself. Indescribing the invention we will refer mainly to the nose carried by theadapter and to the tooth point carried thereby. In the type of adapternose and point commonly employed today, the nose has a generallywedge-shaped contour and the surfaces of this contour contact similarinternal surfaces in the tooth point.

The most effective tooth is one that successfully resistsrupture-inducing stresses applied by the ground being worked andsimultaneously remains tightly inter-engaged. These desirablecharacteristics have not been simultaneously possible of attainment.Neither could be sacrificed, so both were compromised.

In ground working, the principal reaction on the composite tooth is in avertical plane, the ground being resistive to being upset and therebyproducing pivoting of the tooth in the vertical plane. The presence ofrocks, hardness of ground, etc., all tend to aggravate this potentialpivoting. Any pivoting in an essentially rigid structure produces wearand, therefore, looseness of fit. The more this pivoting occurs, thesooner the tooth must be replaced which means unproductive down-time inan expensive piece of equipment for which there is usually nosubstitute.

The acknowledged expedient of improving lit in wedgeshaped inter-engagedmembers is to elongate the wedge shape. This is unavailable here sinceit would render the tooth weak so that any extraordinary stress mightrupture it.

In those devices Where particularly harsh stresses are encountered, suchas rippers and the like, the tooth is required to be relatively smallandthis feature complicates the problem. The usual wedge, in the past, hadto be additionally tapered, i.e., horizontally as well as vertically, inorder to perform under these harsh conditions. This meant that anyvertical pivoting of the point relative to the nose changed the fullbearing area of the side surfaces to a point contact. In other words,any pivotal movement of the tooth changes it from a full bearing area toa point contact, the point contact being one back corner of the pointopposite to the direction in which the tooth is moved. This pointcontact, by

directing the full force of the impact thereon, causes excessive wearand greatly shortens the life of the tooth point.

It is an object of this invention to provide a novel tooth structurewhich is effective to resist both internal wear and rupture. In anembodiment of the invention this is achieved by providing mating arcuatecontours on the side faces of the tooth elements. The principal stressis taken by the adapter or nose-providing element and this element alsodetermines just how good a wedge fit can be obtained. By providing thiselement with convex side walls, both desirable characteristics areachieved.

Another object is to provide a nose-providing element which iswedge-shaped in side elevation with a side wall (preferably both) beingoutwardly rounded as by including a segmental surface generated about anaxis generally normal to the side wall. In this structure, a conformingpoint, when pivoted vertically, maintains a line of contact irrespectiveof its angular orientation, thereby minimizing wear and the possibilityof premature failure. At the same time, the nose element is equippedwith a thicker section so as to better resist stresses, and this thickersection simultaneously provides a greater area of bearing contact toreduce wear and without the need for the disadvantageous elongation ofthe wedge.

Still another object is to provide a tooth point with a Wedge-shapedsocket, the socket being equipped with at least one and preferably twoopposed, generally vertically-extending side walls, concave in contourand being segmental surfaces of revolution with the revolution axisbeing perpendicular to the length of the point and in a horizontalplane.

A further object is to provide a combination of nose and socket elementsunited by keys or other means whereby the points may swing verticallyrelative to each other to a limited extent while at the same timeproviding wide areas of contact between the members during each portionof such travel so that a large bearing surface is provided between themembers under heavy load and irrespective of the relative position ofthe two members.

Yet another object is to provide in ground working dew'ces, nose andsocket elements wherein the nose is provided with a cone surface orspherical surface or other surface of revolution contacting acorresponding surface of the socket element, thus enabling the parts tomove in a vertical are relative to each other with the bearing surfacesof the two members substantially in full contact.

A still further object is to provide a ground Working device having anovel internal configuration, i.e., the mating surfaces of the nose andpoint--the nose particularly being characterized by a square-like end orbox shape that projects from the forwardly tapered faces of the nose. Ayet further object is to provide a tooth structure wherein the point andnose are equipped with a generally square-type projection at the socketapex and in which the point is shaped in a novel fashion to provide apick-type penetrating end. Other objects and advantages of the inventionmay be seen in the details of construction and operation as set forth inthe following portion of the specification.

The invention will be described in conjunction with the accompanyingdrawing, in which- FiG. 1 is a fragmentary elevational view, partiallyin phantom line, of a ground-working device equipped with a toothembodying the invention, the ground level for two positions of the toothbeing shown, one level being in dashed line; FIG. 2 is an exploded sideelevational view of the shank and tooth portion of FIG. 1; FIG. 3 is atop elevational view of the point and nose portions of the tooth as seenin FIG. 2 and also featuring these elements in exploded relation; FIG. 4is a front end elevational view of the nose portion seen in FIGS. 2 and3;

FIG. 5 is a view similar to FIG, 4 but of the point portion; FIGS. 6 and7 are sectional views taken along the lines 6-6 and 7-7, respectively,of FIG. 3; and FIG. 8 is a top elevational view, partially inlongitudinal section, of a modified form of tooth.

Referring now to the drawing, and in particular FIG. 1, the numeral 10designates generally a ground-working tool or device. The specific formillustrated is a ripper which includes an elongated, generallyvertically-extending shank 11 and a tooth 12. The tool 10 is pivotallyconnected by means of an articulatable frame 13 to a tractor 14, thetractor being shown in phantom line. The ground level is indicated bythe numeral 15.

In the operation of the equipment just described, the ripper is movedforwardly by the tractor 14 in a position beneath the surface of theground 15 and is operative to upset the ground, which usually is quitehard or ditlicult to dig. It is believed that this particular type oftooth 12 and its associated structure illustrates one of the mostdifficult jobs to be performed by ground-working equipment. Softerground may be simultaneously loosened and excavated by diggers, draglinebuckets, etc., all of which are also conventionally equipped with teeth.Irrespective of the environment, however, the tooth is subjected totremendous forces tending to pivot it about its mounting on the shank 11and in a generally vertical plane. However, when the ripper is enteringthe ground or scarifying, the point is at an angle to ground level, thelevel of the ground under this condiiton being designated by the numeral115, and the forces are reversed, as indicated. Thus, the tooth must beable to withstand forces in both directions.

A mentioned hereinbefore, the tooth usually includes a point and anadapter. These can be seen in enlarged form in F165. 2 and 3, where thepoint is designated by the numeral 16 and the adapter or nose isdesignated by the numeral 17. In the view seen in FIG. 2, the adapter 17is seen to be mounted on the shank or base 11, and this connection isachieved in a rigid fashion by means of a locking key or pin (notshown). Alternatively, the adapter 17 may he provided as an integralpart of the base 11, as by welding.

The adapter 17 and the point or cap 16 may be fastened together by meansof a retainer key 18 which is installed in openings 18a in adapter 17and 18b in point 16, when these openings are aligned as seen in FIG. 1.In some instances, a press fit between the point 16 and the adapter 17may be adequate to maintain these two elements in inter-engagement, inwhich case the locking means, consisting of the pin 18 and the openings18a and 1817, can be dispensed with.

In the illustration given, the adapter is generally wedgeshaped, i.e.,the adapter 17 tapers inwardly toward the point-receiving end thereof.The point 16 is equipped with a socket 16a (see also FIG. 7) which isadapted to receive the adapter or nose 17.

As can be appreciated from a comparison of FIGS. 2 and 3, the tooth ofthe specific illustration given tapers both in the horizontal andvertical directions. In other words, the upper and lower surfaces 19 and2t) converge as one proceeds toward the end of the nose or adapter 17a.In like fashion, the side walls 21 and 22 also converge as one proceedstoward the end 17a. The corresponding surfaces of the socket 16a of thepoint 16 are similarly convergent, as can be appreciated from acomparison of FIGS. 2 and 3 relative to the top and bottom surfaces 23and 24-, respectively, and the side surfaces 25 and 26, respectively,each of which is seen only in dashed line since these surfaces arehidden in the elevational views presented. However, the surface 26 canbe seen in FIG. 7.

Attention is now directed to the surfaces 21 and 22 on the sides of thenose or adapter 17 and with the corresponding longitudinally-extendingvertical side surfaces 25 and '26 in the point 16. Each of the foursurfaces just mentioned is, in the illustration given, an arcuatesurface developed or generated by rotating an imaginary line about ahoribontal axis extending transversely of the length of the tooth. Theaxis of generation is designated by the numeral 27 relative to theadapter 17 and by the numeral 27a relative to the point 16. When thepoint and adapter are inter-engaged, the two axes are substantiallycolinear.

In the illustration given and with reference to FlG- URES 27, thesurfaces 21, 22, 25 and 26 each include a conical segment. Thedevelopment of this segmental surface can be appreciated from aconsideration of FIGURE 5 in which the axis 27a is seen and in whichimaginary lines 2712 are also seen. The lines 27b, with the axis 27aform a triangle and the solid of revolution generated by this structureis a cone. Where the angles formed between the lines 27b and the axis27a are acute angles as shown, the cone developed will be a double endedcone, hence, each of the surfaces 20, 21, 25 and 26 will include aconical segment. It is apparent, however, that by arranging one of thelines 27b at a right angle to the axis 27a that a single ended cone willbe developed. In such a case, only one pair of corresponding bearingsurfaces would be conical, i.e., surfaces '22 and 26 or surfaces 21 and25.

The conical surfaces provided herein are segmental in that they areinterrupted in a vertical direction by the top and bottom surfaces ofthe adapter 17 or the top and bottom surfaces 23 and 24 of socket 16a,as the case may be. In some cases, it may be advantageous also toprovide the upper and lower bearing surfaces (19 and 20 in adapter 17,and 23 and 24 in socket 16a) with an arcuate surface of the natureprovided relative to the side surfaces, i.e., the generally verticallyand longitudinally extending surfaces.

Surface contours other than conical may be employed in the practice ofthe invention and one such alternative surface can be seen in FIGURE 8.In that figure, the modified nose is designated by the numeral 117 andthe tapered surface 121 is seen to include a spherical segment. Thiswould be achieved by revolving a circular arc in place of the straightline 27b of FIGURE 5. For purposes of comparison the location of theconical surface is indicated in FIGURE 8 by a dotted line to which thenumeral 21 is applied. However, by comparing the opposite side 122 withthe side 22 of FIGURE 3, it will be seen that irrespective of thesurface of revolution employed, there is a curvature provided thatexists in a vertical plane and which is helpful in achieving thebenefits alluded to hereinbefore.

From the foregoing, it will be appreciated that the contour of the sidesurfaces 21 and 22 provide a thickened section in the nose 17 resultingin greater strength and without the heretofore necessary disadvantageouswidening of the wedge angle. Widening of the wedge angle results in lesseffective bearing surface for the desirable tight fit between the noseand point. Also, the provision of additional metal in the area of theadapter 17 receiving the impact of ground working stresses results in asuperior operation when there is relative movement between the point andadapter. Any pivotal movement of the point 16 relative to the adapter 17is accompanied by an entire line of bearing rather than just a pointcontact-the latter necessarily being productive of greater wear.

In the illustration given, the adapter 17 is provided with a box-shapedend 17a which can be readily appreciated from a consideration of FIGURES2 and 3. The surfaces making up the box-shaped end 17a are essentiallyfiat, with the side surfaces 21a and 22a being essentially perpendicularto the axis 27. In other words, the surfaces 21a and 22a are parallel tothe plane of pivotal action which the tooth follows under the impact ofground working stresses. A similar configuration, i.e., box-shapedrecess is provided at the extreme inner end of socket 16athis beingdesignated by the numeral 28 in FIGURE 7.

' When the tooth is under any pressure which is normally encountered indigging, the point tends to move forward on the top surface of the nose.This forward movement of the top portion of the point places a strain onany retaining key or pin, if one is provided as at 18. In the ordinarytooth, it is the keystone that tends to hold the point back in positionon its normal bearing surface. However, through the provision of thesquare nose tip in the inventive tooth, the point cannot follow itsnormal course down the inclined top surface without tending to raise upand ride over the square end. For the point to raise up and ride overthe square end, its direction of travel would necessarily have to bedirectly opposed to the force which created the downward travel in thefirst place.

We have found that this desirable reverse stress action can be obtainedwith very short end projectionsof the order of approximately A1" to /2long, varying somewhat with the size of the tooth and the strength ofthe material. Here, it is to be appreciated that the term square asapplied to this projection 17a is employed in its sense of denoting thatthe nose end is provided by surfaces approximating a box shape, theprecise crosssectional configuration depending upon the width and taperof the four nose-forming faces rearward of the box tip. Generally, theprojection 17a will have a rectangular cross section.

For the advantageous tooth operation described above, a projection 17aconstituting less than -15% of the nose length is very effective, andwith harder materials of construction, nose projections of 45% the noselength (measured from the tip to the shoulder against which the rear ofthe point bears) may be employed advantageously.

v The box tip 17a of the nose 17 may be advantageously rounded in theupper forward edge thereof, as at 17b of FIG. 2. For example, acurvature of as little as that provided by a A? radius in maximum sizedteeth may be effective in prolonging the life of a tooth. This roundingeflfectively prevents peening of the box end which may result from thedistorting force that is applied hundreds of times each diggingoperation. This peening results in working the top surface of the tip17:: and

ultimately may result in a shear failure of the tip. The

lower forward edge may be similarly rounded to permit readyreversibility of the point .on the nose.

We have found that curvatures having radii less than about 25% of thelength of the tip 1711 are effective in resisting undesirable strainsuch as would result from the above-described peening. In other words,for a boxshaped tip 17a having a length of /z (measured in the directionof nose length), the radius of curvature should be less than about A;and excellent results are obtainable with curvatures substantially less.

Also cooperating with the box-shaped tip projection on the nose tostabilize the point, is the conforming point socket portion 28. Theupper point portion adjacent the socket portion 28 is made somewhatthicker as at 29 (see FIG. 2) to aid in this stabilizing actiontherebybetter resisting any deformation-producing forces applied to the pointby the box-shaped tip. This upper wall (adjacent the area designated bythe numeral 29) provides the usual spike portion associated with apoint.

The ground-engaging end 39 of the point 16 may be made essentially pic-shaped for superior ripping action. This is achieved in theillustration given by beveling the point 16 as at 31 (again see FIG. 2).From this, it is seen that there is a massive point portion, orreinforced area, between the socket tip and the point tip. The point 16is also equipped with integral, rearwardly-extending tongues 32 whichmate with corresponding recesses in the adapter-equipped shank 11.

The angle between the nose inclined upper surface 19.

and the upper surface of the box-shaped projection 17a on the nose 17 isof the order of about A similar angle exists between the lower nosesurface 20 and the lower flat surface of the box-shaped projection 17a.A slightly greater angle exists between the upper interior wall 23 ofthe socket 16a and the upper surface of the socket apex 28-the anglebeing about 1 greater than the corresponding angle in the nose 17. Thesame larger angle is found to exist between the lower wall of theboxshaped socket 28 and the lower wall 24. We also find it advantageousto provide the socket apex, i.e., in the box-shaped portion, about /s orso greater in height than the height of the nose tip 17a. The differentangularity in the socket and nose therefore provides initial contactbetween the point and the nose at the extreme rear of the point andpermitting slight play at the forward portion. This play is immediatelytaken up on the application of any digging force by engagement of theflat surfaces of the nose projection 17a and the conforming socket 28 ofthe point 16. This initial contact brings about the desirable reversalof force direction mentioned above so as to stabilize the point on thenose. Thus, by slightly exaggerating the angle in the socket (ascontrasted to the nose tip), we insure that the box-providing surfacesmake initial contact so that there is a pressure fit in the tooth ratherthan a mechanically designed fit. This is efiective even where thelength of the nose projection is relatively short, i.e., the noseprojection constituting less than about 15% of the length of the nose,measured from the shoulder of the adapter against which the point bears.

While, in the foregoing specification, we have set forth a detaileddescription of the invention for the purpose of explanation thereof,many variations in the details herein given may be made by those skilledin the art without departing from the spirit and scope of the invention.

We claim:

1. An excavating tooth, comprising a socket member and a nose membersubject to vertical stresses, said nose member being equipped with alongitudinally tapered nose and said socket member being equipped with alongitudinally tapered socket conforming to said nose and in which saidnose is removably mounted, said socket having at least one arcuate sidebearing surface fitting a corresponding arcuate side bearing surface onsaid nose, each of said side bearing surfaces being flanked and definedby upper and lower portions, said bearing surfaces being generallyvertical and including surfaces of revolution having a common axis ofgeneration extending horizontally and transversely of the length of saidmembers, the removable mounting of said members coupled with wear on theconfronting upper and lower portions of said nose and socket necessarilyresulting from said stresses permitting relative vertical movementbetween said nose member and socket member when a vertical stress isapplied, said bearing surfaces remaining in fitting engagement duringrelative vertical movement of said members.

2. An excavating tooth, comprising a socket member and a nose membersubject to vertical stresses, said nose member being equipped with alongitudinally tapered nose and said socket member being equipped with alongitudinally tapered socket conforming to said nose and in which saidnose is removably mounted, said socket having at least one arcuate sidebearing surface fitting a corresponding arcuate side bearing surface onsaid nose, each of said side bearing surfaces being flanked and definedby upper and lower portions, said bearing surfaces being generallyvertical and including surfaces of revolution having a common axis ofgeneration extending horizontally and transversely of the length of saidmembers, the removable mounting of said members coupled with wear on theconfronting upper and lower portions of said nose and socket necessarilyresulting from said stresses per- '4 mitting relative vertical movementbetween said nose member and socket member when a vertical stress isapplied, said bearing surfaces remaining in fitting engagement duringrelative vertical movement of said members, said nose being equippedwith a box-shaped tip and said socket being equipped with an apexgenerally conforming to said tip.

3. An excavating tooth, comprising a socket member and a nose membersubject to vertical stresses, said nose member being equipped with alongitudinally tapered nose and said socket member being equipped with alongitudinally tapered socket conforming to said nose and in which saidnose is removably mounted, said socket having at least one arcuate sidebearing surface fitting a corresponding arcuate side bearing surface onsaid nose, each of said side bearing surfaces being flanked and definedby upper and lower portions, said bearing surfaces being generallyvertical and including surfaces of revolution having a common axis ofgeneration extending horizontally and transversely of the length of saidmembers, the removable mounting of said members coupled with wear on theconfronting upper and lower portions of said nose and socket necessarilyresulting from said stresses permitting relative vertical movementbetween said nose member and socket member when a vertical stress isapplied, said bearing surfaces remaining in fitting engagement duringrelative vertical movement of said members, and pin means extendingtransversely through said members for interconnecting said members, saidpin means being effective to maintain said members in coupled conditionwithout interfering with said relative vertical movement.

4. An excavating tooth, comprising a point and an adapter subject tovertical stresses, said adapter being equipped with a longitudinallytapered nose and said point being equipped with a longitudinally taperedsocket conforming generally to said nose and in which said nose isremovably mounted, said socket being equipped with a pair of opposedside bearing surfaces fitting a pair of corresponding arcuate sidebearing surfaces on said nose, said side bearing surfaces being fiankedand defined by upper and lower portions on said nose and said socket,said bearing surfaces being generally vertical and including surfaces ofrevolution having a common axis of generation extending horizontally andtransversely of the length of said nose, the removable mounting of saidpoint on said adapter coupled with wear on the confronting upper andlower portions of said nose and socket neces sarily resulting from saidstresses permitting vertical movement of said point on said adapter whena vertical stress is applied to said point, said bearing surfacesremaining in fitting contact during said vertical movement.

5. An excavating tooth, comprising a point and an adapter subject tovertical stresses, said adapter being equipped with a longitudinallytapered nose and said point being equipped with a longitudinally taperedsocket conforming generally to said nose and in which said nose isremovably mounted, said socket being equipped with a pair of opposedside bearing surfaces fitting a pair of corresponding arcuate sidebearing surfaces on said nose, said side bearing surfaces being flankedand defined by upper and lower portions on said nose and said socket,said bearing surfaces being generally vertical and including surfaces ofrevolution having a common axis of generation extending horizontally andtransversely of the length of said nose, the removable mounting of saidpoint on said adapter coupled with wear on the confronting upper andlower portions of said nose and socket necessarily resulting from saidstresses permitting vertical movement of said point on said adapter whena vertical stress is applied to said point,'said bearing surfacesremaining in fitting contact during said vertical movement, said nosebeing equipped with a socket-shaped tip and said socket being equippedwith an apex generally conforming to said tip.

6. An excavating tooth, comprising a point and an adapter subject tovertical stresses, said adapter being equipped with a longitudinallytapered nose and said point being equipped with a longitudinally taperedsocket conforming generally to said nose and in which said nose isremovably mounted, said socket being equipped with a pair of opposedside bearing surfaces fitting a pair of corresponding side bearingsurfaces on said nose, said side bearing surfaces being flanked anddefined by upper and lower portions on each of said nose and socket,said bearing surfaces being generally vertical and each pair includingsurfaces of revolution generated by revolving two nonparallel imaginarylines about a single axis of generation common to both pairs andextending horizontally and transversely the length of said nose, theremovable mounting coupled with wear on the confronting upper and lowerportions of said nose and socket necessarily resulting from saidstresses permitting vertical movement of said point on said adapter whena vertical stress is applied to said point, said bearing surfacesremaining in fitting contact during said vertical movement.

7. A tooth point for an excavating tooth subject to vertical stresses,comprising a point having a support portion adapted to fit a supportmember with limited vertical movement between said point and supportmember, said support portion having generally vertically andlongitudinally-extending nonparallel side bearing surfaces, at least oneof said bearing surfaces including an arcuate surface of revolutionhaving an axis of generation perpendicular to said plane and beinginterrupted and flanked by the top and bottom edges of said supportportion, said surfaces being adapted to be in full mating contact withsaid side surfaces on said support member during said vertical movement.

8. A replaceable excavating point subject to vertical stresses,comprising a spike portion integral with and projecting forwardly fromthe supporting portion, said supporting portion being equipped withvertically and longitudinally-extending side bearing surfaces adapted toengage similariy extending side bearing surfaces on the tooth pointsupport, said point being adapted to move vertically relative to saidsupport when a vertical stress is applied, said bearing surfaces on saidtooth point being generally convergent in a direction longitudinally ofthe tooth point, said bearing surfaces including surfaces of revolutionhaving a common axis of generation adjacent the rear of said supportingportion and extending horizontally and transversely of the length of thepoint, the side bearing surfaces of said point being adapted to remainin fitting engagement with the support side surfaces during saidrelative vertical movement.

9. A tooth point subject to vertical stresses, comprising a generallywedge-shaped body terminating in a digging edge and equipped with awedge-shaped socket, said socket being defined by convergent upper andlower walls and a pair of generally vertically-extending side walls,said side walls including arcuate surfaces of revolution generated abouta horizontal axis extending generally parallel to said edge, said socketbeing adapted to releasably receive a correspondingly shaped nose of atooth adapter and when so arranged said body being adapted to movevertically on said adapter when a vertical stress is applied, said bodyside walls remaining in mating contact with the corresponding side wallsof said nose during vertical movement of said body relative to saidadapter.

10. A tooth point subject to vertical stresses, compris ing a generallywedge-shaped body terminating in a digging edge and equipped with awedge-shaped socket, said socket being defined by convergent upper andlower walls and a pair of generally vertically-extending side walls,said side walls including arcuate surfaces of revolution generated abouta horizontal axis extending generally parallel to said edge, said socketbeing adapted to releasably receive a correspondingly shaped nose of atooth adapter and when so arranged said body being adapted to movevertically on said adapter when a vertical stress is applied, said bodyside walls remaining in mating contact with the corresponding side wallsof said nose during vertical movement of said body relative to saidadapter, said socket being equipped with a box-shaped apex and alignedapertures in opposite walls thereof for receiving a pin for releasablylocking said body on the adapter.

11. A tooth point subject to vertical stresses, comprising aWedge-shaped point having convergent outer top and bottom wallsextending longitudinally thereof to define a Wedge shape, a generallyWedge-shaped socket in said point generally aligned with the wedge shapedefined by said outer walls, said socket having at least one generallyvertically-extending side wall, said socket being adapted to releasablyreceive a correspondingly contoured adapter nose for mounting the pointon the adapter, said point When so mounted being adapted to movevertically relative to said adapter When a vertical stress is applied,said side wall including a surface of revolution generated about ahorizontal axis extending transversely of the length of said point, saidside wall being adapted to remain in fitting engagement with acorresponding side wall of the adapter nose during movement of saidpoint relative to the adapter.

12. A tooth point adapted to be releasably mounted on a support memberand upon being subjected to a vertical stress being adapted to movevertically relative to said member, said point comprising an elongatebody equipped with a socket at one end adapted to mate with said memberand a digging edge at the other end, said socket being equipped with avertical arcuate surface adapted to remain in bearing contact with acorresponding surface of said member during the vertical movement ofsaid point on said member, said surface being a surface of revolutiongenerated about a horizontal axis extending transversely of the lengthof said body, said socket having a box-shaped apex.

13. An adapter for supporting a releasable excavating tooth pointprojecting forwardly therefrom and subject to vertical stressesproducing relative vertical movement of the point on the adapter, saidadapter having verticallyextending side bearing surfaces adapted toengage corresponding side bearing surfaces on the tooth point, at leastone of said bearing surfaces including a surface of revolution having anaxis of generation adjacent the rearward portion thereof, said axis ofgeneration extending in an approximately horizontal direction and normalto the length of the adapter, said side bearing surfaces of said adapteradapted to remain in mating contact with the point corresponding sidebearing surfaces during said relative vertical movement.

14. An adapter for supporting a replaceable excavating tooth pointprojecting forwardly therefrom and subject to vertical stressesproducing relative vertical movement of the point on the adapter, saidadapter having a nose partially defined by generally vertically andlongitudinallyextending side bearing surfaces adapted to engagecorresponding side bearing surfaces on the tooth point, said bearingsurfaces being generally convergent in their longitudinal direction,each of said bearing surfaces including an arcuate surface of revolutionhaving an axis of generation adjacent the rearward portion thereof, saidaxis of generation extending in an approximately horizontal directionand normal to the length of said adapter, said side bearing surfaces ofsaid adapter adapted to remain in mating contact with the pointcorresponding side bearing surfaces during said relative verticalmovement.

15 An adapter for supporting a replaceable excavating tooth pointprojecting forwardly therefrom and subject to vertical stressesproducing relative vertical movement of the point on the adapter, saidadapter having a nose partially defined by generally vertically andlongitudinallyextending side bearing surfaces adapted to engagecorresponding side bearing surfaces on the tooth point, said bearingsurfaces being generally convergent in their longitudinal direction,each of said bearing surfaces including an arcuate surface of revolutionhaving an axis of generation adjacent the rearward portion thereof, saidaxis of generation extending in an approximately horizontal directionand normal to the length of said adapter, said side bearing surfaces ofsaid adapter adapted to remain in mating contact with the pointcorresponding side hearing surfaces during said relative verticalmovement, said nose being equipped with a box-shaped tip.

References Cited in the file of this patent UNITED STATES PATENTS2,666,272 Everett Ian. 19, 1954- 2,716,822 Launder Sept. 6, 19552,915,290 Petersen Dec. 1, 1959 2,919,506 Larsen Jan. 5, 1969

